High spatial resolution particle detectors

Abstract

Disclosed below are representative embodiments of methods, apparatus, and systems for detecting particles, such as radiation or charged particles. One exemplary embodiment disclosed herein is particle detector comprising an optical fiber with a first end and second end opposite the first end. The optical fiber of this embodiment further comprises a doped region at the first end and a non-doped region adjacent to the doped region. The doped region of the optical fiber is configured to scintillate upon interaction with a target particle, thereby generating one or more photons that propagate through the optical fiber and to the second end. Embodiments of the disclosed technology can be used in a variety of applications, including associated particle imaging and cold neutron scattering.

What is claimed is: 
     
       1. A method, comprising:
 partially doping end portions of optical fibers to a dopant depth with one or more doping agents, the one or more doping agents and the dopant depth being selected to scintillate with and improve detection of a target particle type at the partially doped end portions when the one or more doping agents are activated by the target particle type, to reduce sensitivity to false target particles or background noise, and to improve spatial resolution and reduce light dispersion by integrating scintillation regions for the target particle type into the optical fibers; 
 performing an annealing process on at least a portion of the partially doped end portions of the optical fibers; and 
 depositing a coating over the end portions of the optical fibers, the partially doped end portions of the optical fibers and the coating together forming a detection surface of a fiber optic face plate; 
 wherein the doping agents are ions and wherein the partially doping comprises: 
 implanting the ions into the end portions of the optical fibers; and 
 varying an implantation energy so that the implanted ions have the dopant depth in the end portions of the optical fibers selected to scintillate with and improve detection of the target particle type. 
 
     
     
       2. The method of  claim 1 , wherein the coating is formed of a material that blocks transmission of one or more untargeted particles. 
     
     
       3. The method of  claim 1 , wherein the coating is aluminum. 
     
     
       4. The method of  claim 1 , wherein the ions comprise one or more of cerium ions, europium ions, or praseodymium ions, and wherein the dopant depth is selected to scintillate with an alpha particle. 
     
     
       5. The method of  claim 4 , wherein the dopant depth is 20 microns or less. 
     
     
       6. The method of  claim 1 , wherein the one or more doping agents and the dopant depth are further selected to scintillate upon interaction with a particle of the target particle type having a selected particle energy. 
     
     
       7. The method of  claim 1 , wherein the one or more doping agents and the dopant depth are further selected to scintillate upon interaction with a particle of the target particle type having a selected particle energy and being generated by a monoenergetic source at a fixed geometric location from the fiber optic face plate. 
     
     
       8. The method of  claim 1 , wherein the doping the end portions of the optical fibers comprises doping the end portions of the optical fibers with two doping agents, a first of the two doping agents selected to generate a secondary particle from the target particle type and a second of the two doping agents selected to generate a photon from the secondary particle. 
     
     
       9. The method of  claim 8 , wherein the first doping agent and the second doping agent are implanted in a consecutive order in which the second doping agent is implanted first and the first doping agent is implanted second. 
     
     
       10. The method of  claim 1 , wherein the coating is formed of a material that blocks transmission of one or more untargeted particles, including photons, and reflects photons generated within the optical fibers, thereby increasing effective light output of the optical fibers. 
     
     
       11. A method, comprising:
 partially doping end portions of optical fibers to a dopant depth with one or more doping agents, the one or more doping agents and the dopant depth being selected to scintillate with and improve detection of a target particle type at the partially doped end portions when the one or more doping agents are activated by the target particle type, to reduce sensitivity to false target particles or background noise, and to improve spatial resolution and reduce light dispersion by integrating scintillation regions for the target particle type into the optical fibers; 
 performing an annealing process on at least a portion of the partially doped end portions of the optical fibers; and 
 depositing a coating over the end portions of the optical fibers, the partially doped end portions of the optical fibers and the coating together forming a detection surface of a fiber optic face plate, 
 wherein the doping agents are ions and wherein the partially doping comprises diffusing the ions into the end portions of the optical fibers to the dopant depth selected to scintillate with and improve the detection of the target particle type. 
 
     
     
       12. The method of  claim 11 , wherein the ions comprise one or more of lithium ions or boron ions, and wherein the target particle type is a neutron. 
     
     
       13. The method of  claim 12 , wherein the depth is between 10 and 60 microns. 
     
     
       14. A method, comprising:
 partially doping end portions of optical fibers to a dopant depth with one or more doping agents, the one or more doping agents and the dopant depth being selected to scintillate with and improve detection of a target particle type at the partially doped end portions when the one or more doping agents are activated by the target particle type, to reduce sensitivity to false target particles or background noise, and to improve spatial resolution and reduce light dispersion by integrating scintillation regions for the target particle type into the optical fibers; 
 performing an annealing process on at least a portion of the partially doped end portions of the optical fibers; 
 depositing a coating over the end portions of the optical fibers, the partially doped end portions of the optical fibers and the coating together forming a detection surface of a fiber optic face plate, wherein the fiber optic face plate is configured to detect a spatial location on the detection surface where the target particle type interacts; and 
 coupling undoped ends of the optical fibers that are opposite of the partially doped end portions to corresponding pixel regions of a pixelated photomultiplier, the coupling being a direct coupling or indirect coupling through an intermediate light guide. 
 
     
     
       15. The method of  claim 14 , wherein the pixelated photomultiplier is part of an imaging system configured to detect the time and location of an interaction of the target particle type with the fiber optic face plate from a monoenergetic source of the target particle type positioned at a fixed geometric location from the fiber optic face plate. 
     
     
       16. The method of  claim 15 , wherein the pixelated photomultiplier is part of an associated particle imaging system.